The present invention relates generally to a motion stabilizer for a combined vehicle which includes a tractor and a trailer connected to the tractor, and particularly to a motion stabilizer in which an engine torque control is exercised to limit an engine torque upon detection of a pendular motion of a tractor.
JP 2002-503185 A (also published under WO99/51475A and U.S. Pat. No. 6,494,281 B1) discloses a motion stabilizer for a combined vehicle in which control exercised if a lateral motion characteristic value is greater than a threshold value involves a control of reducing an engine torque as well as a control of applying brakes.
When a tractor making a pendular motion starts shifting to a stabilized state thanks to a braking control and an engine torque limiting control (trailer stability control), a driver sometimes feels that the vehicle is in a stabilized state, even before a pendular motion imparted to the tractor is sufficiently reduced. In such an instance, the driver may depress the accelerator in an attempt to accelerate the vehicle; however, in a case where the engine torque limiting control is configured to go on until the trailer stability control comes to an end, the driver would feel uncomfortable because his/her attempts to accelerate the vehicle would fail due to the limited engine torque.
Against this backdrop, there is a need to provide a motion stabilizer for a combined vehicle, in which a braking control and an engine torque limiting control are exercised in response to detection of a pendular motion of a tractor, and which provides an improvement in a feel of drive which would possibly be impaired when the motion of the tractor starts shifting to a stabilized state.